The present invention relates to an electronic musical instrument capable of independently transmitting only a MIDI message.
Recent electronic musical instruments, such as an electronic piano, an electronic organ and a synthesizer, have a function to transmit and receive MIDI messages. In such an electronic musical instrument, data, which is generated by operating keys on a keyboard or switches on a control panel, is supplied to a tone generator to be used to generate musical tones, or is converted to data in a format conforming to MIDI standards (this data will be called "MIDI message") and is then sent outside the electronic musical instrument. A MIDI message externally sent to the electronic musical instrument is supplied to the tone generator and is used to generate musical tones.
Many recent electronic musical instruments have an automatic performance function. The use of this automatic performance function permits a player to enjoy playing an instrument by playing a specific part while automatically playing several parts. For instance, while generating musical tones of accompaniment parts, such as a drum part, a base part and a chord part, by using the automatic performance function, the player can play a melody part with the timbre of a trumpet.
This automatic performance function is accomplished in the following manner. Automatic performance data, stored part by part in a memory of a sequencer externally connected to the electronic musical instrument or in a memory of the electronic musical instrument, and is sequentially read out from the memory, is sequentially sent to individual tone generators associated with the respective parts. The tone generators simultaneously produce tone signals based on which the associated musical tones are generated. To accomplish the automatic performance function, therefore, the same number of the tone generators as the number of the parts is required. The provision of the tone generators equal in number to the parts increases the cost, so that a multi-tone generator, which will simultaneously generate the musical tones of a plurality of the parts, has been developed and become popular recently.
One of those multi-tone generators, called a multi-timbre tone generator can efficiently perform the automatic performance, and thus becomes very popular. The multi-timbre tone generator can generate a plurality of timbres at a time, and can arbitrarily select an oscillator that will be assigned to the tone generation of each part. In other words, in the multi-timbre tone generator, each oscillator is not assigned previously to each of the parts, but the number of the oscillator to be assigned to each part is determined and also it is determined what numbered oscillator is assigned, when tone generation is requested, and thus such multi-timbre tone generator has an advantage in permitting the effective use of a limited number of the oscillators.
In preparing the aforementioned automatic performance data of a plurality of the parts, for example, a scheme called "over dubbing" is used. In the "over dubbing", automatic performance data of a specific part is prepared first and recorded, and then automatic performance data of another part is prepared and recorded while generating musical tones based on the previously recorded automatic performance data of the specific part. Thereafter, the above operation is repeated to sequentially prepare automatic performance data of all the necessary parts and record the data.
FIG. 6 illustrates an example of the system structure which executes the over dubbing. In FIG. 6, reference numeral "50" denotes a keyboard equipped with a tone generator which becomes a "master", reference numeral "51" denotes a sequencer, and reference numeral "52" denotes, for example, a multi-timbre tone generator unit which becomes a "slave". The MIDI output terminal of the keyboard 50 is connected to the MIDI input terminal of the sequencer 51. The MIDI output terminal of the sequencer 51 is connected to the MIDI input terminal of the keyboard 50 and the MIDI input terminal of the tone generator unit 52.
In preparing automatic performance data and recording the data using this system structure, first, a player sets the keyboard 50 to a local OFF mode. Then, the player operates the keyboard 50 to play a specific part of a piece of music, for example, a bass part. Accordingly, a MIDI message is output from the MIDI output terminal of the keyboard 50 and is supplied to the sequencer 51. In the sequencer 51, the received MIDI message is stored on a specific track (e.g., the first track) and the received MIDI message is echoed back to the keyboard 50. The echo back causes the same data as the MIDI message stored in the sequencer 51 to be supplied to the tone generator of the keyboard 50, thereby generating musical tones.
When the preparation and recording of automatic performance data of the specific part are completed in the above manner, the sequencer 51 is activated. Consequently, the MIDI message of the specific part previously recorded on the first track in the sequencer 51 is transmitted to the tone generator unit 52, which in turn generates musical tones.
While listening the thus generated musical tones of the specific part, the player then performs an operation to prepare and record automatic performance data of another part. More specifically, as the player plays the keyboard 50, a MIDI message is output from the MIDI output terminal of the keyboard 50 and is supplied to the sequencer 51. In the sequencer 51, the received MIDI message is recorded on a different track (e.g., the second track) from the first track, and is echoed back to the keyboard 50. The echo back causes the tone generator of the keyboard 50 to generate musical tones based on the same data as the MIDI message stored in the sequencer 51. At this time, the generation of musical tones according to the MIDI message recorded on the first track from the tone generator unit 52 continues.
Thereafter, automatic performance data of the individual parts are prepared and are sequentially recorded on the respective tracks in the sequencer 51 until the preparation and recording of automatic performance data of all the parts are finished. Accordingly, the preparation and recording of automatic performance data of one piece of music are completed.
According to the conventional electronic musical instrument, when an event on a predetermined switch on the control panel (e.g., a timbre switch, a volume switch, etc.) is detected, tone control data (data for controlling the characteristic of a musical tone, such as a timbre number for determining the timbre or the volume value for determining the volume), which corresponds to the event-detected switch, is produced and is stored in a predetermined memory. At the same time, a MIDI message associated with that switch (e.g., a program change message, a control change message, etc.) is produced and sent outside the electronic musical instrument.
When the depression of a key on the keyboard is detected, generated is a musical tone having the pitch corresponding to the depressed key and having the timbre, volume, etc. based on the tone control data stored in the memory, and, at the same time, a MIDI message (note-ON message) corresponding to the key-depression event is produced and sent outside the electronic musical instrument. When the release of a key on the keyboard is detected, tone off of the musical tone, which is currently being generated and is associated with the released key, is carried out. At the same time, a MIDI message (note-OFF message) corresponding to the key-release event is produced and is sent outside the electronic musical instrument.
Because the conventional electronic musical instrument has the above-described structure, in changing the timbre of a musical tone to be generated by the tone generator unit 52, in the over-dubbing system shown in FIG. 6, the operation mode of the sequencer 51 should be set to the mode for outputting a MIDI message, which has been inputted to the MIDI input terminal, directly to the MIDI output terminal, and the timbre switch on the keyboard 50 should be operated to generate a program change message and to send the program change message outside the electronic musical instrument. Consequently, the program change message is supplied to the tone generator unit 52 through the sequencer 51 to permit the alteration of the timbre of the musical tone that is generated from the tone generator unit 52.
When the timbre switch on the keyboard 50 is operated, however, the tone control data (timbre number) stored in the aforementioned memory is also changed. This changes the timbre of the musical tone which is being generated from the tone generator incorporated in the keyboard 50. Accordingly, the timbre of the musical tone which is generated from the tone generator incorporated in the keyboard 50 may become different from what is intended by the player, so that the over dubbing with the timbre intended by the player cannot be carried out.